csb

iTrader: (1)

Hi. As mentioned, a 2000 Maxima (5-speed, for what it's worth). Here are the exact symptoms: starts perfectly (even in the cold), then develops a somewhat sputtering, unstable idle within 20 seconds. The sputtering/unstable idle goes away and becomes completely smooth. Next, when I set out to drive the car initially, it's "herky-jerky" at the lower RPM's. That goes away once the car has warmed up. Next symptoms, after it's warmed up: there is an intermittent, minor hesitation (or lack of smoothness) during moderate-hard acceleration throughout the rev-range, AND the car will occasionally stall out when the clutch pedal is depressed as I approach a stop. The RPM's dip to 200 or so...sometimes catch and come back up to ~800, sometimes don't and it kills. It will always restart normally and idle perfectly once this has happened. Then...it may kill again, at any time, in the same way. I originally had a "bank 1, sensor 2" code and have since replaced that sensor (behind the cat...fed spec). No codes at all presently...haven't had any for several hundred miles. I replaced the MAF with a used one and the car behaves exactly the same way as with the original MAF. Does anyone have any ideas OR can anyone link me to another thread with similarities? Thanks!!!

MoncefA33

iTrader: (6)

Try a new MAF sensor.

The idle issue could be your IACV as well.

csb

iTrader: (1)

It's just that, since I've already tried one MAF (albeit, a used one), I don't really want to buy another...especially since the car's behaving the same and I have zero codes. As for the IACV, I thought about that. Do you know where it is located? Thanks for the response...

P. Samson

If you search you'll lots of info (and history) on the IACV. A quick check of the basic IACV operation is to listen for a sound like a "buzz" when you turn the ignition sw. from OFF to ON, (wait a second or so) and then from ON to OFF (helps to have a second person). The IACV assembly is bolted to the underside of the TB.......you'll see the two coolant hoses and one harness connector (attached to the stepper motor) that are attached to it (the other harness connector is for the TPS). The stepper motor (has a black housing) that controls the airflow (commanded by the ECM) is attached with two screws. I would first CAREFULLY (don't flood the TB with fluids) clean the TB bore in the area of the throttle plate with a toothbrush and carb/TB cleaner. See if that improves the idle control issue. If not, then remove the stepper motor (leave the harness connector attached and don't pull or push on the pintle) and suction/vacuum/clean the TB/IACV housing air passage. Check for ANY signs of coolant. Past history shows that the stepper motor can get contaminated with coolant and fail.

rman

Make sure you check for air/vacuume leaks.

P. Samson

As rman has suggested check for any vacuum leaks. There have also been intake manifold gasket leaks supposedly on these cars. I would also check that the PCV valve and hose is flowing air. Pull it (still attached to the hose) out of the camshaft cover and check that there is vacuum at the end of it with the engine idling.

csb

iTrader: (1)

Removed the throttle body, IACV and EGR today...cleaned them all, put them back and...all fixed. Idles perfectly, runs perfectly, doesn't kill, still no codes. Happy camper...thanks to all who contributed. To the others...where were you when I needed you?